NEC Code Allowance for Breaker Exceeding 250% Amp Rating?

H

hou628

Member
For a current project, an existing 25HP blower (continuous) is installed with a 100A breaker. Per NEC 430.250 the FLC, is 34A meaning the 250% breaker sizing would be 85A. I believe the 100A was chosen as the motor will be replaced in the future to 50HP.



Questions:
  1. For the current setup, is the 100A acceptable per NEC code OR should the breaker size be reduced to 80A?
  2. If the load was not continuous would the 100A be acceptable?


Thanks!
 
1) The 100 amp OCPD is not acceptable as the next standard size up from 85 is 90 amps.
2) Continuous operation of the blower has nothing to do with it.
 
Thank you for the reply. Just to understand, is 90A acceptable even though the current would exceed 250% or should it be reduced to the safer direction of 80A?
 
For a single motor the next standard size up is permitted. Since 85 amps is not a standard size in Table 240.6 the next size up (90 amps) is permitted. For all intents and purposes 80 amps will work too.
 
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